The Irish Times has reported government officials have found there are 208 crossings traversing the 310 mile frontier.

Emails between officials from the Northern Ireland Department for Infrastructure and the Department of Transport in the Republic reveal the “nightmare” of trying to map out all roads, paths and dirt tracks along the border.

There was confusion about crossings where the border runs up the middle of roads or where roads are privately owned on one side and publicly maintained on the other.

The mapping exercise, which started last year, came to light after being referred to in minutes released under Freedom of Information.

Map of the Irish border (PA Graphics)

The border runs along the middle of 11 roads, more than twice the number originally estimated, while the frontier meets in the middle of at least three bridges and two ferry crossings.

Previous estimates put the number of road crossings between Ireland and Northern Ireland at 275.

The issue of how to deal with the border has been one of the major sticking points in the Brexit negotiations between the UK government and the EU.

There are only 137 crossings along the entire border between the whole of the EU and all of the countries to the east of the bloc.

In one of the emails between Belfast and Dublin, an official said: “I’m now getting 208 border crossings in total, hope you are too.”

Another official said the final report on border crossings may have to have a disclaimer.

“With something so ambiguous as the border there will be a few metres out here and there,” he said.

Another added: “There are practical implications when it comes to roads that are split along the middle that probably can’t be represented on maps; but that is as good a way of representing it.”

It is understood the final report will be made public in the coming weeks.